Fig. 4. Significant reduction of late pachytene spermatocytes in Scmh1^-/- testes. (A) Reduction of late pachytene spermatocytes in spermatocyte spread prepared from day 18 pp Scmh1^-/- testes in comparison with wild type. Spermatocytes were immunostained using anti-Scp3 (red) and uH2A (green). (Left) Wild-type spermatocytes, in which uH2A is enriched at the XY body, were examined at early or late pachytene stage, based on Scp3 immunostaining and morphology. (Right) Frequency of early and late pachytene spermatocytes was compared between the wild-type and Scmh1^-/- testes. (B) Localization of Mlh1 in spermatocytes. (Ba) Spermatocytes of wild type were immunostained by using anti-Scp3 (red) and Mlh1 (green). (Bb) Higher magnification view of chromosomes shown in a. (Bc) Localization of Mlh1 in Scmh1^-/- mutant testes. (Bd) Higher magnification view of chromosomes shown in c. Arrows in b and d indicate Mlh1 foci.